1. Technical Field
The present invention relates to an image forming method using an inkjet method.
2. Background Art
As an image recording method by an inkjet method, a method is known in which recording is performed by ejecting an ink in a droplet from a large number of nozzle provided on an inkjet head. This method enables a high speed image formation, and widely used because, for example, a high quality image can be recorded on a wide variety of recording media.
For a colorant which is one of ingredients of ink material, a pigment is widely used, and the pigment is used by being dispersed in a medium such as water. In the case where the pigment is used in the form of dispersion, dispersed particle size when the pigment is dispersed, stability and size uniformity after dispersion, ejection performance from ejection head, image density and the like are important. A variety of studies on techniques for improving these properties are conducted.
On the other hand, in the case where an image is recorded by an inkjet method, the durability of the recorded image is one of important properties from the viewpoint quality. Among properties which represent the durability of an image, improvement of rub fastness is tried. For example, an ink for inkjet recording that contains water-based resin emulsion in the ink for the purpose of fixing a film of the ink is disclosed (see, for example, Japanese Patent Application Laid-Open (JP-A) No. 2006-249203).
Further, for improvement purpose of seeming rub fastness by enhancing slipping property of an image, use of wax particles is known. For example, a printing method is attempted in which resin ink containing resin particles and wax particles are used in combination with a color ink to perform an inkjet recording on a non-ink-absorptive or low-ink-absorptive recording medium (see, for example, JP-A No. 2010-105187). It is said that this method is excellent in image quality and rub fastness, irrespective of ink-absorptive properties of the recording media.
On the other hand, it is well-known that a base material is subjected to a pretreatment for the purpose of improving ink adhesion. For example, an example in which a nonwoven fabric fiber web is subjected to a surface treatment such as corona treatment is known (see, for example, Japanese Application National Phase Publication No. 2011-513049).
In addition, it is disclosed that when an image is formed on a non-ink-absorptive or low-absorptive recording medium by using an aqueous ink composition, an aqueous ink composition containing wax particles and polymer particles is used (see, for example, JP-A No. 2010-90266).
Further, an inkjet recording method by which bleeding along a fiber is suppressed to a large extent in the case of printing on a cloth (see, for example, JP-A No. 2009-259446). Further, it is disclosed that after subjecting a non-ink-absorptive image-recording surface to a hydrophilication treatment, an image is formed by using an inkjet recording apparatus (see, for example, JP-A No. 2004-90596).
In the case where an ink image is formed on a recording medium such as a nonwoven fabric made of a non-absorptive or low-absorptive synthetic fiber such as polypropylene, since the fiber itself does not absorb an ink, the ink is hard to be fixed. For this reason, the image has poor rubfastness and also the image is inferior in texture such as a hand feeling of the image, which easily poses a problem for quality of the image.
Among the above-mentioned conventional techniques, in the ink for inkjet recording that employs a water-based resin emulsion, an image is formed by using polymer particles. In the case where an image is recorded on a base material made of the above-mentioned non-absorptive or low-absorptive fiber (nonwoven fabric or the like), the image is not yet satisfactory in terms of rubfastness. Accordingly, further improvement is required.
The above-mentioned recording media is generally known to have a poor ink adhesion, and sufficient rub fastness of the image cannot be necessarily obtained only by simply containing resin particles and wax particles in the ink as in the above-mentioned printing method in which printing is performed on non-absorptive or low-absorptive recording media.
To subject a base material to a surface treatment such as a corona treatment as in the above-mentioned Japanese Application National Phase Publication No. 2011-513049 is effective for improvement of ink adhesion. However, adhesion enough to maintain rub fastness cannot be obtained only by the surface treatment, and for example, drying and fixing treatment of the ink are required. When the base material is non-absorptive or low-absorptive, sufficient drying of the ink is hard to be performed, and the amount of ejected droplet is not always properly controlled, which poses a problem for bleeding of image.
Further, regarding a recording medium in the above-mentioned JP-A No. 2010-90266, art paper, coat paper and the like as well as a plastic film are exemplified as an ink-low absorptive recording medium. However, a quality of an image formed on a medium composed of a non-absorptive or low-absorptive fiber is not taken into consideration.
Further, in the above-mentioned JP-A No. 2009-259446, incorporation of a predetermined amount of wax together with an aqueous dispersion type polymer such as a urethane polymer as ink components is not proposed.
The present invention was made in view of the above-mentioned circumstances. An object of the present invention is to provide an image forming method in which an image having a good texture such as hand feeling (for example, without hardness and stickiness of an image) and an excellent rub fastness is formed by employing a nonwoven fabric made of a non-ink-absorptive or low-absorptive fiber, and the present invention aims to attain the object.